Google Play closed test tracker: 12 testers for 14 days
New personal Play accounts need 12 testers opted in for the 14 days right before they apply for production. Play Console shows a count, not who joined when. List your testers here and see the earliest day you can apply.
Who counts
A tester counts once they have been opted in at your closed-test link for 14 days in a row and are still in. Accepting the invite is the opt-in; being on the email list or Google Group alone is not.
Dropouts
Someone who opts out before day 14 doesn't count at all. If they opt back in, their 14 days start again: set their opt-in date to the day they rejoined and clear the "left on" date.
The chance figure
Each tester is assumed to stay with the same chance, from the dropout rate you set, prorated to the days left. With exactly 12 testers and a 10% dropout, the odds of all 12 lasting 14 days are 28%.
The rule as Google states it, how many testers to recruit and a day-by-day plan: Google Play's 12 testers for 14 days rule. Days are calendar days; leave a day of margin around time zones. Your list stays in this browser.